Add RW memory layout TE #36
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| This type defines the layout of a region of read-write memory that a client can | ||
| allocate into its memory map. If other memory types are required (i.e. | ||
| read-only memory), separate TE's should be defined. |
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This sounds very specific to a single project (TF-A?), so it should probably go in the TE section for that. At least I wouldn't know from this description what to do with this entry if I encountered it in my firmware.
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You're probably right. The structure this TE represents is fairly simple:
typedef struct meminfo {
uintptr_t total_base;
size_t total_size;
} meminfo_t;This to me seems adaptable to other contexts, although i'm yet to find any concrete examples. In any case, I've moved it to TF-A's namespace. If a more general use case materialises then we can consider adding it back.
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XFERLIST_RW_MEM_LAYOUT64 is used to specify an extent of read-write memory that a client can use. The TE pertains to TF-A and is relevant only for 64-bit architectures. Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
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| extent of memory it has available to perform read-write operations on. BL2 maps | ||
| the memory described by the layout into its memory map during platform setup. If | ||
| other memory types are required (i.e. read-only memory) separate TE's should be | ||
| defined. |
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Would it be useful to generalise this to include any 'next phase'??
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What do you mean? I refer to its usage in BL2 here only as a concrete example, but it very well could be used in other places.
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OK, then please put 'For example, ...' in a separate paragraph so it is clear
source/transfer_list.rst
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| **Read-Write Memory Layout Entry Layout (XFERLIST_RW_MEM_LAYOUT64)** | ||
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| This entry type holds a structure that describes the layout of a read-write | ||
| memory region. TF-A defines this structure and uses it to convey to BL2 the |
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Should the sentences after the first be written as an example? It seems that this information could be used elsewhere
source/transfer_list.rst
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| extent of memory it has available to perform read-write operations on. BL2 maps | ||
| the memory described by the layout into its memory map during platform setup. If | ||
| other memory types are required (i.e. read-only memory) separate TE's should be | ||
| defined. |
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OK, then please put 'For example, ...' in a separate paragraph so it is clear
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
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| * - size | ||
| - 8 | ||
| - hdr_size + 8 |
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
`TL_TAG_RW_MEM_LAYOUT64` encapsulates a structure used to represent the layout of a region of memory on 64-bit platforms [2]. In TF-A this is used to represent the `meminfo_t` structure passed between BL1 and BL2, which provides BL2 with information about the space it has available in BL2. The `TL_TAG_TB_FW_CONFIG` entry type encapsulates the trusted bootloader firmware configuration [1]. [1] FirmwareHandoff/firmware_handoff#37 [2] FirmwareHandoff/firmware_handoff#36 Change-Id: I1e0eeec2ec204e469896490d42a9dce9b1b2f209 Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
XFERLIST_RW_MEM_LAYOUT64 is used to specify an extent of read-write memory that a client can use. Note, in future if other memory types need representation seperate TE's should be defined (left in the layout description as a point of discussion).